Thymeleaf系列四生成URL地址和表达式工具对象

曾经终败给现在 2021-09-12 08:14 266阅读 0赞

## 1. 概述 ##

本节的标准表达式语法包含如下内容：

*  生成URL地址:@\{\}
 *  表达式工具对象:Expression Utility Objects

## 2. 主代码 ##

### 2.1. 公共代码 ###

ExpressionsCtl：Control类

@Controller
    @RequestMapping("/expressions")
    public class ExpressionsCtl { 
        /** * 处理URL * * @param modeMap * @return */
        @RequestMapping("/url")
        public String url(ModelMap modeMap){
            modeMap.put("id", "123");
            return "expressions/url";
        }
    
        /** * 表达式工具对象:Expression Utility Objects * */
        @RequestMapping("/utility")
        public String utility(ModelMap modeMap){
            return "expressions/utility";
        }
    }

url()方法转到url.html, 包含urls的用法代码; utility()方法转到utility.html，包含表达式工具对象相关代码。

### 2.2. 生成URL地址@\{\} ###

演示如下功能

*  th:href生成的值替换的href值 @\{\}
 *  url中加入变量值(orderId=$\{id\})做为url的请求参数

==================== 动态生成URL =============================== 
 
 http://localhost:8080/gtvg/order/details?orderId=123 --> <a href="details.html" th:href="@{http://localhost:8080/gtvg/order/details(orderId=${id})}">view</a> 
 
 
 /order/details?orderId=123 --> <a href="details.html" th:href="@{/order/details(orderId=${id})}">view</a> 
 
 
 /order/123/details --> <a href="details.html" th:href="@{/order/{orderId}/details(orderId=${id})}">view</a>

输出: “–>”的左边是语法，右边是对应的输出(这里以源码方式显示)

==================== 动态生成URL =============================== 
 
 http://localhost:8080/gtvg/order/details?orderId=123 --> <a href="http://localhost:8080/gtvg/order/details?orderId=123">view</a> 
 
 
 /order/details?orderId=123 --> <a href="/order/details?orderId=123">view</a> 
 
 
 /order/123/details --> <a href="/order/123/details">view</a>

### 2.3. 表达式工具对象:Expression Utility Objects ###

thymeleaf有很多工具类，所有工具类如下：

*  \#execInfo: information about the template being processed.
 *  \#messages: methods for obtaining externalized messages inside variables expressions, in the same way as they would be obtained  
    using \#\{…\} syntax.
 *  \#uris: methods for escaping parts of URLs/URIs
 *  \#conversions: methods for executing the configured conversion service (if any).
 *  \#dates: methods for java.util.Date objects: formatting,  
    component extraction, etc.
 *  \#calendars: analogous to \#dates, but for  
    java.util.Calendar objects.
 *  \#numbers: methods for formatting  
    numeric objects.
 *  \#strings: methods for String objects: contains,  
    startsWith, prepending/appending, etc.
 *  \#objects: methods for objects in general.
 *  \#bools: methods for boolean evaluation.
 *  \#arrays: methods for arrays.
 *  \#lists: methods for lists.
 *  \#sets: methods for sets.
 *  \#maps: methods for maps.
 *  \#aggregates: methods for creating aggregates on arrays or collections.
 *  \#ids: methods for dealing with id attributes that might be repeated (for example, as a result of an iteration).

这里只列出\#messages，\#uris的用法，其它工具类用法见[官方的用法详细见这里][Link 1]，

==================== #messages =============================== 
 
 ${#messages.msgOrNull('home.welcome.replace','message')} --> 
 
 
 ==================== #uris =============================== 
 
 ${#uris.escapePath('http://blog.csdn.net/hry2015/')} -->

输出: “–>”的左边是语法，右边是对应的输出

==================== #messages ===============================
    ${ #messages.msgOrNull('home.welcome.replace','message')} --> welcome thymeleaf, message! 
    ==================== #uris ===============================
    ${ #uris.escapePath('http://blog.csdn.net/hry2015/')} --> http://blog.csdn.net/hry2015/

## 3. 代码 ##

详细代码见[Github][]

[Link 1]: http://www.thymeleaf.org/doc/tutorials/3.0/usingthymeleaf.html#appendix-b-expression-utility-objects
[Github]: https://github.com/hryou0922/spring_boot/tree/master/thymeleaf/src/main/java/com/hry/spring/expressions